Google claims that its service is the "world's largest public Domain Name Server (DNS) recursive resolver"; it turns domain names into IP addresses required for communication on the Internet.

DNS-over-TLS and DNS-over-HTTPS are two approaches to making DNS requests more private by using encryption. One of the main differences between the two implementations is the port that is used. DNS-over-TLS uses port 853, DNS-over-HTTPS the standard HTTPS port 443.